Wikipedia

Stichodactyla mertensii

Mertens' carpet sea anemone (Stichodactyla mertensii) is a species of stichodactylidsea anemones. It is regarded as the largest sea anemone with a diameter of over 1 m (3.3 ft), the next largest being Heteractis magnifica which has longer tentacles.[2] This species has an oral disc that can be described as more ovoid than circular that contours to the surrounding substrate and is attached to the substrate by adhesive verrucae, which are wart like projections.[3] Its blunt or pointed tentacles are uniformly shaped, and are only about 1–2 centimetres (0.39–0.79 in) long.[2] While this species can be confused with Stichodactyla gigantea and S. haddoni, they are most easily distinguished by habitat since the former two prefer sand while S. mertensii prefers rocky or coral substrate.[3] It contains obligate symbiotic zooxanthellae, and can serve as a host anemone to 17 separate fish species, the majority of which are anemonefish, with one damselfish.